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Thermography is a well-established non-destructive testing technique in materials research and defect detection. In addition, it is used on cultural heritage in the form of buildings and paintings. This contribution explores the utilisation of active thermography on an object of technical heritage – a historic aircraft of the Second World War, the Messerschmitt Me 163 b, as a part of an exhibition in the Deutsches Museum in Munich. Unfortunately, the appearances of many exhibits in museums have been altered before or during their time with the museum and are not in a historically accurate condition. Furthermore, the active service history is often not documented in detail or might have been lost. Both features are equally important in the presentation of information on a displayed item and destructive techniques cannot be employed on historic objects. Hence a non-destructive, non-contact way of examination was chosen in the form of thermography. With the help of phase analysis, flash thermography is also an invaluable tool for the evaluation of layered systems and can differentiate between paint layers. During the research presented herein, traces of abrasion and chemical stripping of older paint layers were visible. This complicates the compilation of sufficient information for a historically accurate restauration with any technique. Nonetheless, flash or pulsed thermography proves to be capable of finding not only identifying markings, defects, and different paint layers, but also the inner workings and substructure of the object under investigation.

Thermography is a non-destructive testing technique which is non-contacting as well as imaging and therefore advantageous for delicate materials. It is more widely used for qualitative evaluation but can also provide data for a quantitative analysis when the heat source is actively controlled. With flash thermography, fast diffusion or conduction processes can be monitored, providing an effective method for the inspection of metals and thin coatings. Ceramic layered systems are used as thermal barrier coatings, for example on turbine blades. Gas turbines with such blades can be operated at higher temperatures, which leads to an increase in efficiency. To fully exploit this advantage, the properties and thickness of the coating must be within a predefined parameter range. Due to the challenging and hard to monitor manufacturing process, the coating must be examined afterwards. With the help of a numerical model using a finite difference solution, multiple material parameters such as thermal conductivity and layer thickness can be determined simultaneously with nonlinear regression fitting. During the research presented herein, a four-stepped sample of ceramic coatings on an Inconel steel basis is examined and the thermographic data analysed. After the thermographic measurements, the sample was cut, embedded in resin, and polished. The scanning electron microscopy images and measurements serve as the reference values to compare the extracted parameters to.